2014年5月
Effect of extending the photoperiod with low-intensity red or far-red light on the timing of shoot elongation and flower-bud formation of 1-year-old Japanese pear (Pyrus pyrifolia)
TREE PHYSIOLOGY
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- ,
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- 巻
- 34
- 号
- 5
- 開始ページ
- 534
- 終了ページ
- 546
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1093/treephys/tpu033
- 出版者・発行元
- OXFORD UNIV PRESS
To investigate the effects of light quality (wavelength) on shoot elongation and flower-bud formation in Japanese pear (Pyrus pyrifolia (Burm. f.) Nakai), we treated 1-year-old trees with the following: (i) 8 h sunlight + 16 h dark (SD); (ii) 8 h sunlight + 16 h red light (LD(SD + R)); or (iii) 8 h sunlight + 16 h far-red (FR) light (LD(SD + FR)) daily for 4 months from early April (before the spring flush) until early August in 2009 and 2010. In both years, shoot elongation stopped earlier in the LD(SD + FR) treatment than in the SD and LD(SD + R) treatments. After 4 months of treatments, 21% (2009) or 40% (2010) of LD(SD + FR)-treated trees formed flower buds in the shoot apices, whereas all the shoot apices from SD or LD(SD + R)-treated plants remained vegetative. With an additional experiment conducted in 2012, we confirmed that FR light at 730 nm was the most efficacious wavelength to induce flower-bud formation. Reverse transcription-quantitative polymerase chain reaction revealed that the expression of two floral meristem identity gene orthologues, LEAFY (PpLFY2a) and APETALA1 (PpMADS2-1a), were up-regulated in the shoot apex of LD(SD + FR). In contrast, the expression of a flowering repressor gene, TERMINAL FLOWER 1 (PpTFL1-1a, PpTFL1-2a), was down-regulated. In addition, expression of an orthologue of the flower-promoting gene FLOWERING LOCUS T (PpFT1a) was positively correlated with flower-bud formation, although the expression of another orthologue, PpFT2a, was negatively correlated with shoot growth. Biologically active cytokinin and gibberellic acid concentrations in shoot apices were reduced with LD(SD + FR) treatment. Taken together, our results indicate that pear plants are able to regulate flowering in response to the R : FR ratio. Furthermore, LD(SD + FR) treatment terminated shoot elongation and subsequent flower-bud formation in the shoot apex at an earlier time, possibly by influencing the expression of flowering-related genes and modifying plant hormone concentrations.
- リンク情報
- ID情報
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- DOI : 10.1093/treephys/tpu033
- ISSN : 0829-318X
- eISSN : 1758-4469
- Web of Science ID : WOS:000337920000009